designing question

[Gordon McMillan]

Pierrette writes:

> I have two questions:
> 1. The database will hold abouth 50.000 lines in its biggest table,
> can gadfly handle this without problems, what abouth acces time ??

Gadfly is in-memory, and (to support transactions) has 2 copies of 
the db. If the machines have the memory, access time will be fine.

> 2. The application will have abouth 50 different inputscreens wich
> acces all to different tables. I will create a class for every
> window wich inheret from a general 'input-screen'-class. I wonder if
> a should place the db-access code (insert-update-delete) in every
> specific window or if i should  create a big db class wich has all
> possible db-acces in it ? 

Completely philosophical question. For flexibility, I favor the GUI 
making no assumptions about how the data is stored. I would have the 
GUI making calls like "app.addthingie(thingie)", where the app has an 
"abstract" UI.

Of course, it almost nevers works out that cleanly in practice, but 
it's certainly a worthy goal.

Now if each screen maps exactly to a table, this is probably 
overkill. But if your data is normalized, this makes a lousy UI - 
users usually want to know all kinds of silly things, like whether 
there's a "next" record, or the owning customer's name (not the 
foreign key in this row, which is just a number) that violate 
normalization.

- Gordon